Usual methods of mechanically treating sheet metal surfaces to impart desired surface properties thereto have hitherto involved grinding, polishing or embossing of the sheet metal surface. In substantially all embossing processes, the negative structure or contour of the desired surface texture of the sheet metal is formed on an embossing body which can be a plate, a roll or a bonding and which is pressed against the sheet metal workpiece.
Since such embossing bodies must be fabricated for each structure to be imparted to the sheet metal, the embossing bodies are rather costly. Furthermore, they tend to wear and must be replaced or resurfaced at comparatively high cost. When large quantities of sheet metal must be processed, the apparatus used is relatively complex since exact positioning of the embossing body is usually required and expensive means must be provided for this purpose.
Furthermore, it must be ensured that no dirt or chips lodge between the embossing body and the sheet metal.
As a consequence, it is necessary at specified intervals to clean the embossing body. In addition, the treated surface of the sheet metal must often be protected from dust and damage by packing the sheet metal or covering the treated surface with a foil which can be stripped off prior to use.